Facile and fast synthesis of highly active Lewis acid MWW zeolite from pure silica ITQ-1

Abstract

A facile hydrothermal etching-healing strategy is proposed to fabricate Sn-MWW zeolite based on a pure silica ITQ-1 precursor, which avoids using any supporting agents and additives, such as B3+ and...

Fabrication of a ZIF-on-lamella-zeolite architecture as a highly efficient catalyst for aldol condensation

“…The Si-MWW zeolite was synthesized following previously reported procedures. 36 Initially, 12.88 g of N,N,N -trimethyl-1-adamantammonium hydroxide (TMAdaOH, 25 wt%) was mixed with 48.31 g of deionized water. Then, 1.87 g of hexamethyleneimine (HMI, 98 wt%) was added to the above solution under stirring.…”

“…4d). 36 Apart from the Si-OH rich feature of Si-MWW, the flat surface and large in-plane dimension also contribute to its optimal support capability, providing ample space for holding the nanoparticles. To confirm the central role of Si-MWW in constructing the special hybrid structure, pure silica zeolites with different structures and surface properties (Si-Beta, 48 Silicalite-1 49 and Si-SPP 50 ) were used to prepare the composite using the same synthesis strategy.…”

“…Building upon our prior expertise in ZIF synthesis and MWW zeolite preparation, 35,36 we developed a step-wise seedassisted regrowth methodology to engineer a ZIF-67/MWW composite, involving the "hatching" of ZIF-67 seeds onto the surface of the Si-MWW zeolite through ultrasonication, followed by a secondary growth process. As a result, finely controlled ZIF-67 nanoparticles became uniformly and durably affixed to the layered structure of the Si-MWW zeolite through precise modulation.…”

Heteroatom Lewis acid zeolites: synthesis, characterization and application in the conversion of biomass-derived oxygenates

“…[24][25][26] Moreover, the different topologies of Lewis acid zeolites provide distinct confinement effects and shape selectivity. [27][28][29][30] Hence, Lewis acid zeolites may play an increasingly important role in developing new catalytic processes that convert raw resources into fuels and chemicals.…”

Morphology Regulation of Zeolite MWW via Classical/Nonclassical Crystallization Pathways

“…MWW zeolite consists of 10 membered rings (MRs) (4 Å × 5.9 Å), a two-dimensional interlayer sinusoidal channel and the 12-ring supercages (7.1 Å × 7.1 Å × 18.2 Å) connected by 10 MR apertures, which have been widely investigated acting as efficient catalysts in the alkylation, isomerization, and disproportionation reactions [ 1 , 2 , 3 , 4 ]. The zeolite type includes MCM-22 [ 5 ], MCM-36 [ 6 ], MCM-49 [ 7 ], MCM-56 [ 8 ], ITQ-1 [ 9 ], ITQ-2 [ 10 ], SSZ-25 [ 11 ], etc.…”